1. Field of the Invention
The invention relates to an antenna coupler for testing transmitters and/or receivers, especially mobile telephones or devices, which operate according to the Bluetooth standard.
2. Related Technology
An antenna coupler for testing mobile telephones is known from DE 197 32 639 C1. With the known antenna coupler, a mounting element for a mobile telephone is attached to a printed circuit board. A rod antenna, which acts, in particular, as a dipole antenna, is formed on the printed circuit board using stripline technology. One substantial property of the antenna coupler is the coupling factor, which specifies the ratio of the received power relative to the total radiated power. Since the known arrangement reacts in an extremely sensitive manner to changes of position of the antenna of the mobile telephone, the coupling factor for each type of mobile telephone attached to the mounting element is different.
Moreover, an antenna coupler for testing mobile transmitters and/or receivers, especially mobile telephones, is known from DE 101 29 408 A1. This antenna coupler provides a mounting element and/or a mounting surface for the mobile transmitter and/or receiver and at least one antenna element. In this context, the antenna element is formed as a loop, which is at least substantially closed in spatial terms.
The particular disadvantage of the antenna couplers described above is that mobile telephones of different structural shapes cannot be arranged in the respective mounting elements in such a manner that a satisfactory coupling to the antenna couplers is guaranteed. As a result, high levels of coupling attenuation occur, which obstruct or completely prevent the testing of the mobile telephones.